Blunt tip surgical cutting device and method

ABSTRACT

A cutting device includes an elongated shaft extending between a proximal end and a distal end. A lower portion extends from the distal end of the elongated shaft and includes an outer surface and an inner surface spaced apart from the outer surface which together form a blunt end configured as a stop so as to protect adjacent tissue. An upper portion extends from the distal end of the elongated shaft and including an inner surface. The upper portion is configured so as to be disposed opposite the lower portion. A cutting element is disposed between the lower portion and the upper portion and is configured for retractable extension beyond the distal end of the elongated shaft so as to contact tissue.

FIELD OF THE INVENTION

The present invention relates generally to devices and methods forcutting a material or substance. More specifically, the devices andmethods are useful for resecting nerve and/or soft tissue via aminimally invasive procedure to alleviate pain.

BACKGROUND OF THE INVENTION

Standard methods of cutting tissue may include using a scalpel,scissors, and radio frequency energy. Electrosurgical procedures andtechniques using radio frequency energy are currently used since theygenerally reduce patient bleeding and trauma associated with cuttingoperations. Additionally, electrosurgical ablation procedures, wheretissue surfaces and volume may be reshaped, cannot be duplicated throughother treatment modalities.

Minimally invasive procedures in nerve and/or soft tissue such as thespine or the breast, however, are difficult to perform using standardscissors and scalpel. Furthermore, in a closed environment, radiofrequency current dissipates into the surrounding tissue causing adecreased ability to achieve a current at the cutting electrode ofsufficiently high density to initiate a cut. To overcome this problem,high power settings are often required to initiate the cut which oftenis painful and increases thermal damage to the tissue whether using astandard or a custom electrosurgical generator.

Another problem associated with cutting tissue is the control ofbleeding. Radio frequency energy controls bleeding by coagulating smallblood vessels. Another method of controlling bleeding is through the useof heat. For example, some commercially available scalpels use directheat to control bleeding. However, while the bleeding is generallycontrolled, the cutting of tissue is often slower than with radiofrequency energy and the knife edge readily dulls. Other commerciallyavailable scalpels use ultrasonic energy generally at 50 kHz to heat thetissue so as to coagulate severed blood vessels but cut slower than astandard electrosurgical electrode and are costly as a custom ultrasonicgenerator is required.

A further disadvantage of using radio frequency energy is the generationof smoke. The smoke is malodorous and can contain airborne viralparticles that may be infectious. Furthermore, the smoke often obscuresvisualization of the procedure. When the smoke becomes too dense, theprocedure is delayed until the smoke is released through one of thetrocar ports and after enough carbon dioxide gas has re-insufflated theabdominal cavity. This unnecessarily prolongs the operative time.

Radiofrequency (RF) energy is used in a wide range of surgicalprocedures because it provides efficient tissue resection andcoagulation and relatively easy access to the target tissues through aportal or cannula. Conventional monopolar high frequency electrosurgicaldevices typically operate by creating a voltage difference between theactive electrode and the target tissue, causing an electrical arc toform across the physical gap between the electrode and tissue. At thepoint of contact of the electric arcs with tissue, rapid tissue heatingoccurs due to high current density between the electrode and tissue.This high current density causes cellular fluids to rapidly vaporizeinto steam, thereby producing a “cutting effect” along the pathway oflocalized tissue heating. Thus, the tissue is parted along the pathwayof evaporated cellular fluid, inducing undesirable collateral tissuedamage in regions surrounding the target tissue site. This collateraltissue damage often causes indiscriminate destruction of tissue,resulting in the loss of the proper function of the tissue. In addition,the device does not remove any tissue directly, but rather depends ondestroying a zone of tissue and allowing the body to eventually removethe destroyed tissue.

Present electrosurgical techniques used for tissue ablation may sufferfrom an inability to provide the ability for fine dissection of softtissue. The distal end of electrosurgical devices are wide and flat,creating a relatively wide area of volumetric tissue removal and makingfine dissections along tissue planes more difficult to achieve becauseof the lack of precision provided by the current tip geometries.

In addition, identification of the plane is more difficult because thelarge ablated area and overall size of the device tip obscures thephysician's view of the surgical field. The inability to provide forfine dissection of soft tissue is a significant disadvantage in usingelectrosurgical techniques for tissue ablation, particularly inarthroscopic, otolaryngological, and spinal procedures.

Traditional monopolar RF systems can provide fine dissectioncapabilities of soft tissue, but may also cause a high level ofcollateral thermal damage. Further, these devices may suffer from aninability to control the depth of necrosis in the tissue being treated.The high heat intensity generated by these systems causes burning andcharring of the surrounding tissue, leading to increased pain and slowerrecovery of the remaining tissue. Further, the desire for anelectrosurgical device to provide for fine dissection of soft tissue maycompromise the ability to provide consistent ablative cutting withoutsignificant collateral damage while allowing for concomitant hemostasisand good coagulation of the remaining tissue.

Another problem with currently available RF nerve ablation devices isthat they attempt to destroy nerve tissue from a central locationincluding the tip of the device and a 3-D spherical or cylindrical zonearound it. As a result, the further away the resecting ability is fromthe central zone the less effective the nerve destruction. Consequently,often the nerve is not adequately ablated leading to continued painsymptoms.

Further, the health care practitioner may have difficulty positioningthe tip of the device in the optimal location to get an optimal andconsistent clinical result. This may also result in unwanted necrosis ofadjacent tissue, which can lead to clinical adverse events includingsubsequent repair of the necrotic tissue.

Other devices such as mechanical rongeurs can be used to remove softtissue. However, these devices require the insertion of relatively largecannulas that further complicate the surgical procedure and can causenerve compression and pain with variable clinical efficacy.

Accordingly, there is a need for devices and methods to provideefficient severing or cutting of nerve and/or soft tissue that can beused during a minimally invasive procedure and/or during an opensurgical procedure. Further, there is also a need for devices andmethods that provide fine dissection capabilities of nerve and/or softtissue. Devices and methods that do not cause a high level of collateralthermal damage and allow for the control of necrosis in the tissue beingtreated are also needed. Devices and methods that provide efficient,controlled and safe debulking of tissue would also be beneficial.

SUMMARY OF THE INVENTION

In accordance with the principles of this disclosure, a cutting deviceis disclosed, which includes an elongated shaft extending between aproximal end and a distal end. A lower portion extends from the distalend of the elongated shaft and includes an outer surface and an innersurface spaced apart from the outer surface which together form a bluntend configured as a stop so as to protect adjacent tissue. An upperportion extends from the distal end of the elongated shaft and includesan inner surface. The upper portion is configured so as to be disposedopposite the lower portion. A cutting element is disposed between thelower portion and the upper portion and is configured for retractableextension beyond the distal end of the elongated shaft so as to contacttissue.

In one embodiment, a cutting device for cutting tissue comprises anelongated shaft extending between a proximal end and a distal end. Alower portion extends from the distal end of the elongated shaft andincludes an outer surface and an inner surface spaced apart from theouter surface which together form a blunt end configured as a stop so asto protect adjacent tissue. An upper portion extends from the distal endof the elongated shaft and includes an inner surface. The upper portionis configured so as to be disposed opposite the lower portion. A cuttingelement is resiliently biased between the lower portion and the upperportion and is configured for retractable extension beyond the distalend of the elongated shaft so as to contact tissue. An attachment to avacuum is disposed at the proximal end of the elongated shaft to producesuction to facilitate removal of tissue from the cavity.

In one embodiment, a method of cutting tissue is disclosed. A cannula isinserted into the anatomy of a patient to form a hole in the tissue. Acutting device is inserted through the cannula. The blunt tip is slidalong a lamina of a patient to prevent damage to tissue. A spring loadedcutting tip is compressed to extend the cutting tip beyond the upper andlower arms to cut tissue. The cutting tip is retracted back into thecavity. The cutting device and the cannula are then removed from thepatient.

Additional features and advantages of various embodiments will be setforth in part in the description that follows, and in part will beapparent from the description, or may be learned by practice of variousembodiments. The objectives and other advantages of various embodimentswill be realized and attained by means of the elements and combinationsparticularly pointed out in the description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In part, other aspects, features, benefits and advantages of theembodiments will be apparent with regard to the following description,appended claims and accompanying drawings where:

FIG. 1 is a side cross sectional view of an embodiment of the device inaccordance with the principles of the present disclosure; and

FIG. 2 is side cross sectional view of an embodiment of the device inaccordance with the principles of the present disclosure.

Like reference numerals indicate similar parts throughout the figures.

DETAILED DESCRIPTION OF THE INVENTION

Devices for efficient severing or cutting of a material or substancesuch as nerve and/or soft tissue suitable for use in open surgicaland/or minimally invasive procedures are disclosed. The followingdescription is presented to enable any person skilled in the art to makeand use the present disclosure. Descriptions of specific embodiments andapplications are provided only as examples and various modificationswill be readily apparent to those skilled in the art.

Lumbar spinal stenosis (LSS) may occur from hypertrophied bone orligamentum flavum, or from a lax ligamentum flavum that collapses intothe spinal canal. LSS can present clinical symptoms such as leg pain andreduced function. Conventional treatments include epidural steroidinjections, laminotomy, and laminectomy. Surgical interventions whichremove at least some portion of the lamina are usually performed througha relatively large incision, and may result in spinal instability fromremoval of a large portion of the lamina. Consequently, a morepercutaneous approach which removes just enough tissue (lamina orligamentum flavum) to be effective may be more beneficial.

In one embodiment, the device includes a cutting tip positioned on adistal end of a spring loaded tool. As the spring is compressed, thecutting tip extends beyond distal end of tool to contact and cut tissue.As the spring is released, the cutting tip retracts into the tool suchthat it does not contact tissue. A blunt distal end of the tool contactsbone to act as stop. The blunt surface is configured to ride along thelamina and may deliver RF energy to the tissue to be cut.

The present disclosure may be understood more readily by reference tothe following detailed description of the disclosure presented inconnection with the accompanying drawings, which together form a part ofthis disclosure. It is to be understood that this disclosure is notlimited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting of the claimed disclosure.

As used in the specification and including the appended claims, thesingular forms “a,” “an,” and “the” include the plural, and reference toa particular numerical value includes at least that particular value,unless the context clearly dictates otherwise.

Ranges may be expressed herein as from “about” or “approximately” oneparticular value and/or to “about” or “approximately” another particularvalue. When such a range is expressed, another embodiment includes fromthe one particular value and/or to the other particular value.

Similarly, when values are expressed as approximations, by use of theantecedent “about,” it will be understood that the particular valueforms another embodiment. It is also understood that all spatialreferences, such as, for example, horizontal, vertical, top, upper,lower, bottom, left and right, are for illustrative purposes only andcan be varied within the scope of the disclosure.

For purposes of the description contained herein, with respect tocomponents and movement of components described herein, “forward” or“distal” (and forms thereof) means forward, toward or in the directionof the forward, distal end of the probe portion of the device that isdescribed herein, and “rearward” or “proximal” (and forms thereof) meansrearward or away from the direction of the forward, distal end of theprobe portion of the device that is described herein. However, it shouldbe understood that these uses of these terms are for purposes ofreference and orientation with respect to the description and drawingsherein, and are not intended to limit the scope of the claims.

Spatially relative terms such as “under”, “below”, “lower”, “over”,“upper”, and the like, are used for ease of description to explain thepositioning of one element relative to a second element. These terms areintended to encompass different orientations of the device in additionto different orientations than those depicted in the figures. Further,terms such as “first”, “second”, and the like, are also used to describevarious elements, regions, sections, etc. and are also not intended tobe limiting. Like terms refer to like elements throughout thedescription.

As used herein, the terms “having”, “containing”, “including”,“comprising” and the like are open ended terms that indicate thepresence of stated elements or features, but do not preclude additionalelements or features.

For purposes of the description contained herein, “vacuum” meanspressure within a space that is lower by any amount than atmospheric orambient pressure, and although not exclusive of a condition of absolutevacuum defined by a complete absence within a space of air, fluid orother matter, the term as used herein is not meant to require or belimited to such a condition.

The headings below are not meant to limit the disclosure in any way;embodiments under any one heading may be used in conjunction withembodiments under any other heading.

Reference will now be made in detail to certain embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention will be described in conjunction with theillustrated embodiments, it will be understood that they are notintended to limit the invention to those embodiments. On the contrary,the invention is intended to cover all alternatives, modifications, andequivalents that may be included within the invention as defined by theappended claims.

Radiofrequency (RF) ablation devices have been available to surgeons totreat many medical conditions, for example, in the treatment of tumorsin lung, liver, kidney, bone and other body organs. Pulsed RF has alsobeen used for treatment of tumors, cardiac arrhythmias, chronic andpost-operative pain, bone fracture and soft tissue wounds.

The components of the cutting device can be fabricated from biologicallyacceptable materials suitable for medical apparatuses, including metals,synthetic polymers, ceramics, thermoplastic and polymeric materialand/or their composites. For example, the components of the holdingdevice, individually or collectively, can be fabricated from materialssuch as stainless steel alloys, commercially pure titanium, titaniumalloys, Grade 5 titanium, super-elastic titanium alloys, cobalt-chromealloys, stainless steel alloys, superelastic metallic alloys (e.g.,Nitinol, super elasto-plastic metals, such as GUM METAL® manufactured byToyota Material Incorporated of Japan, Fe—Mn—Si and Fe—Ni—Co—Ticomposites), ceramics and composites thereof such as calcium phosphate(e.g., SKELITE™ manufactured by Biologix Inc.), thermoplastics such aspolyaryletherketone (PAEK) including polyetheretherketone (PEEK),polyetherketoneketone (PEKK) and polyetherketone (PEK), carbon-PEEKcomposites, PEEK-BaSO4 polymeric rubbers, polyethylene terephthalate(PET), fabric, silicone, polyurethane, silicone-polyurethane copolymersbased materials, polymeric rubbers, polyolefin rubbers, semi-rigid andrigid materials, thermoplastic elastomers, thermoset elastomers,elastomeric composites, rigid polymers including polyphenylene,polyamide, polyimide, polyetherimide, polyethylene, epoxy, andcomposites of metals and calcium-based ceramics, composites of PEEK andcalcium based ceramics, and combinations of the above materials.

Various components of the holding device may have material composites,including the above materials, to achieve various desiredcharacteristics such as strength, rigidity, elasticity, compliance, andbiomechanical performance, durability and to provide a non-sticksurface. The components of the holding device may be monolithicallyformed, extruded, coextruded, hot molded, cold molded, press molded,integrally connected or include fastening elements and/or couplingcomponents, as described herein.

In one embodiment, as shown in FIGS. 1-2, the cutting device 10, inaccordance with the present disclosure, includes an elongated shaft 12.Shaft 12 extends between a proximal end 14 and a distal end 16 anddefines a longitudinal axis L1. It is envisioned that all or only aportion of shaft 12 may have various cross section configurations, suchas, for example, cylindrical, flat, oval, oblong, triangular, square,polygonal, irregular, uniform, non-uniform, offset, staggered,undulating, arcuate, variable and/or tapered. In various embodiments,the navigational sources can be coupled with a pre-procedure such as forexample, CT, MRI, PET scan, etc. so that the target nerve or soft tissueto be cut can be identified and accurately located during the procedure.

A lower portion 18 extends from distal end 16 of shaft 12. Portion 18includes an inner surface 20 and an outer surface 22 spaced apart fromthe inner surface 20. Surfaces 20, 22 together forms a blunt end 24configured as a stop to protect adjacent tissue. It is contemplated thatsurfaces 20 and 22 include various surface configurations, such as, forexample, smooth, rough, mesh, porous, semi-porous, dimpled and/ortextured.

An upper portion 26 extends from distal end 16 of shaft 12 and isdisposed opposite portion 18. Portion 26 includes an inner surface 28.It is contemplated that surface 28 includes various surfaceconfigurations, such as, for example, smooth, rough, mesh, porous,semi-porous, dimpled and/or textured. Surface 20 and surface 28 areconfigured to form a cavity 30. Cavity 30 is configured to house acutting element 32, discussed below. In some embodiments, cavity 30 canhave a cross section being cylindrical, flat, oval, oblong, triangular,square, polygonal, irregular, uniform, non-uniform, offset, staggered,undulating, arcuate, variable and/or tapered.

Device 10 includes a cutting element 32. Cutting element 32 isconfigured to contact and/or cut tissue. Cutting element 32 isresiliently biased, such as, for example, with a spring 34 within cavity30 such that cutting element 32 extends out of cavity 30 to contactand/or cut tissue. In some embodiments, the resiliently biased membercan include a semi-rigid, rigid or elastic configuration, and/or haveelastic properties, such as the elastic properties corresponding to thematerial examples described above, such that the resiliently biasingmember provides a selective amount of expansion, contraction, collapseand/or extension.

In one embodiment, cutting element 32 includes electrodes 36 configuredto emit a RF frequency adapted for cutting nerve and/or soft tissue. Inone embodiment, cutting element 32 is configured to emit pulsed plasmasignals adapted for cutting nerve and/or soft tissue. In one embodiment,device 10 includes an electrically insulated layer adjacent to andexposing cutting element 32 such that the energy transmitted from the RFfrequency and/or the plasma is centralized at cutting element 32. Insome embodiments, the coating or insulating layer can be glass orceramic having a thickness from about 0.005 to about 0.5 mm thick orfrom about 0.01 to about 0.2 mm thick. By moving cutting element 32across tissue, the RF or plasma signals will cut the tissue.

In one embodiment, shaft 12 includes an internal passage 44 configuredto engage a vacuum 46, as shown in FIG. 2, to suction the resected nerveand/or soft tissue. Alternatively, an additional channel is possible fordelivering fluid to the surgical site. At its proximate end, shaft 12can be operatively connected to vacuum 46 for providing suction toresected nerve and/or tissue. Vacuum 46 may be used to transmit vacuumfrom a vacuum source (not shown) to a receiving aperture connected toshaft 12. Any suitable aspirator, cylindrical or otherwise, or othermechanism that creates vacuum upon the movement of an actuating memberthereof, may be utilized as a vacuum source. Vacuum 46 can be in fluidcommunication with cavity 24 for providing suction to remove cut nerveand/or soft tissue.

The present disclosure also provides methods for cutting or resectioningnerve and/or soft tissue. The methods comprise positioning a distalregion of shaft 12 of cutting device 10 adjacent a nerve or soft tissueto be cut. End 24 is blunt so as not to pierce certain areas of thepatient, such as, for example, the spinal cord. In addition, the bluntsurface is configured to ride or follow along a relatively rigidstructure, such as the lamina, and the cutting element advances to atissue distal to the rigid structure, such as the ligamentum flavum.Distal end 16 is positioned at the area where the tissue is to be cut.To cut the tissue, spring 34 is compressed such that cutting element 32moves toward tissue, shown by arrow A, such that cutting element 32 cutsor pierces the tissue. As spring 34 is released, cutting element 32moves back to its original position as shown by arrow B. Vacuum 46 ispositioned within or outside of shaft 12 can be utilized to suction thecut nerve and/or soft tissue such that device 10 can be reinserted foradditional cutting.

In another embodiment, the cutting device defines a small channelconfigured for injection of irrigation fluid to the surgical site towash out the surgical site. The irrigation fluid may also facilitatesuction of loose tissue fragments, and/or to cool ablated tissue.

In one embodiment, shaft 12 is operatively coupled to a source ofnavigational capability to allow easier pushing through the tissues. Invarious embodiments, the methods of cutting disclosed herein can includea pre-procedure step wherein the probe or needle can be coupled to a CT,MRI, PET machine, or the like so that the target nerve and/or softtissue to be cut can be identified and accurately located during theresection procedure.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to various embodimentsdescribed herein without departing from the spirit or scope of theteachings herein. Thus, it is intended that various embodiments coverother modifications and variations of various embodiments within thescope of the present teachings.

What is claimed is:
 1. A cutting device comprising: an elongated shaftextending between a proximal end and a distal end; a lower portionextending from the distal end of the elongated shaft and including anouter surface and an inner surface spaced apart from the outer surfaceand together forming a blunt end configured as a stop so as to protectadjacent tissue; an upper portion extending from the distal end of theelongated shaft including an inner surface, the upper portion configuredso as to be disposed opposite the lower portion; and a cutting elementdisposed between the lower portion and the upper portion and configuredfor retractable extension beyond the distal end of the elongated shaftso as to contact tissue.
 2. A cutting device as recited in claim 1,wherein the inner surface of the lower portion and the inner surface ofthe upper portion form a cavity configured to house the cutting element.3. A cutting device as recited in claim 2, wherein the cutting elementis resiliently biased such that the cutting portion extends out of thecavity so as to contact and cut tissue.
 4. A cutting device as recitedin claim 3, wherein the cutting element is spring loaded such that thecutting portion extends out of the cavity so as to contact and cuttissue.
 5. A cutting device as recited in claim 1, wherein the cuttingelement comprises a cutting tip configured to pierce tissue.
 6. Acutting device as recited in claim 1, wherein the cutting element isconfigured to extend past the blunt end to contact tissue.
 7. A cuttingdevice as recited in claim 1, wherein the cutting element includeselectrodes configured to emit a radio frequency configured to cuttissue.
 8. A cutting device as recited in claim 1, wherein the cuttingelement is configured to emit plasma energy for destruction of tissue.9. A cutting device as recited in claim 1, wherein the elongated shaftfurther includes an attachment to a vacuum to produce suction so as toremove tissue.
 10. A cutting device as recited in claim 5, wherein thedevice includes an electrically insulated layer adjacent to and exposingthe cutting element such that the energy transmitted from the radiofrequency is centralized at the cutting element.
 11. A cutting devicefor cutting tissue comprising: an elongated shaft extending between aproximal end and a distal end; a lower portion extending from the distalend of the elongated shaft and including an outer surface and an innersurface spaced apart from the outer surface and together forming a bluntend configured as a stop so as to protect adjacent tissue; an upperportion extending from the distal end of the elongated shaft includingan inner surface, the upper portion configured so as to be disposedopposite the lower portion; a cutting element being resiliently biasedbetween the lower portion and the upper portion and configured forretractable extension beyond the distal end of the elongated shaft so asto contact tissue; and an attachment to a vacuum disposed at theproximal end of the elongated shaft to produce suction so as to removetissue from the cavity.
 12. A cutting device as recited in claim 10,wherein the inner surface of the lower portion and the inner surface ofthe upper portion form a cavity configured to house the cutting element.13. A cutting device as recited in claim 10, wherein the cutting elementcomprises a cutting tip configured to pierce tissue.
 14. A cuttingdevice as recited in claim 10, wherein the cutting element is configuredto extend past the blunt end to contact tissue.
 15. A cutting device asrecited in claim 11 wherein the cutting element includes electrodesconfigured to emit a radio frequency configured to cut tissue.
 16. Acutting device as recited in claim 11, wherein the cutting is configuredto emit plasma energy for destruction of tissue.
 17. A cutting device asrecited in claim 14, wherein the device includes an electricallyinsulated layer adjacent to and exposing the cutting element such thatthe energy transmitted from the radio frequency is centralized at thecutting element.
 18. A method of cutting tissue comprising: inserting acannula to form a hole in the tissue; inserting a cutting device throughthe cannula, the cutting device comprising: an elongated shaft extendingbetween a proximal end and a distal end; a lower portion extending fromthe distal end of the elongated shaft and including an outer surface andan inner surface space apart from the outer surface and together forminga blunt end configured as a stop so as to protect adjacent tissue; anupper portion extending from the distal end of the elongated shaftincluding an inner surface, the upper portion configured so as to bedisposed opposite the lower portion; a cutting element being resilientlybiased between the lower portion and the upper portion and configuredfor retractable extension beyond the distal end of the elongated shaftso as to contact tissue; and an attachment to a vacuum disposed at theproximal end of the elongated shaft to produce suction so as to removetissue from the cavity; sliding the blunt tip along a lamina of apatient to prevent damage to tissue; compressing a spring of the springloaded cutting tip to extend the cutting tip beyond the upper and lowerarms to cut tissue; retracting the cutting tip into the cavity; andremoving the cutting device and the cannula.
 19. A method of cuttingtissue as recited in claims 18, including the step of capturing the cuttissue in the cavity;
 20. A method of cutting tissue as recited in claim19, including the step of suctioning the cut tissue out of the cavity.